What is Fragile X Syndrome?

Fragile X Syndrome is the most common known inherited cause of learning disabilities, affecting around 1 in 4000 males and 1 in 8000 females. It can cause a wide range of difficulties with learning, as well as social, language, attentional, emotional, and behavioral problems. In addition, approximately 1 in 250 females and 1 in 600 males are carriers of the fragile X pre-mutation. Some carriers may develop symptoms of one of the two Fragile X-associated Disorders. Therefore, fragile X consists of a family of three genetic conditions.

How does Fragile X affect those with the condition?

Fragile X syndrome is a genetic condition that causes a range of developmental problems including learning disabilities and cognitive impairment. Usually, males are more severely affected by this disorder than females.

Affected individuals usually have delayed development of speech and language by age 2. Most males with fragile X syndrome have mild to moderate intellectual disability, while about one-third of affected females are cognitively disabled. Children with fragile X syndrome may also have anxiety and hyperactive behaviour such as fidgeting or impulsive actions. They may have attention deficit disorder (ADD), which includes an impaired ability to maintain attention and difficulty focusing on specific tasks. About one-third of individuals with Fragile X syndrome have features of autism spectrum disorders (ASD) that affect communication and social interaction. Seizures occur in about 15 percent of males and about 5 percent of females with fragile X syndrome.

Most males and about half of females with fragile X syndrome have characteristic physical features that become more apparent with age. These features include a long and narrow face, large ears, a prominent jaw and forehead, unusually flexible fingers, flat feet, and in males, enlarged testicles (macroorchidism) after puberty.

Fragile X Society